Heat exchanger with tubular elements, especially for hot-water and superheated-water heating boilers



July 31, 1962 e. ROSS] HEAT EXCHANGER WITH TUBULAR ELEMENTS, ESPECIALLY FOR HOT-WATER AND SUPERHEATED-WATER HEATING BOILERS 2 Sheets-Sheet 1 Filed June 25, 1957 INVENTOR. Giovanni K055i July 31, 1962 G. ROSSI 3,046,955

HEAT EXCHANGER WITH TUBULAR ELEMENTS, ESPECIALLY FOR HGT-WATER AND SUPERHEATED-WATER HEATING BOILERS Filed June 25, 195'? 2 Sheets-Sheet 2 7 F F /E.4

ELK V INVENTOR:

United States Patent The present invention relates to a heat exchanger with tubular elements, especially intended for use in connection with hot-water and superheated-water heating boilers.

In the operation of heat exchangers of the conventional type, and especially of heating boilers used to produce hot-water and superheated water, the feeding and distribution of the liquid cause the water to circulate according to preferential directions, thus provoking a nonuniform transmission of the heat, and, as a consequence, peak pressures not accompanied by a corresponding uniform increase of the temperatures, breakages due to local overheating, corrosion of the colder surfaces due to deposit from the combustion gases, etc.

Such defects are eliminated by using a device according to the present invention, which is substantially char acterized by this, that it comprises at least one conduit bringing in the water supply and/or the liquid coming back, through the return piping, to the upper collector, or header, said conduit being equipped with truncated tubes partially entering the downcomers, the latter having an inner diameter substantially larger than the outer diameter of said truncated tubes in order to prevent the colder liquid to come directlyin contact with the tubes exposed to heat, to obtain a pre-heating of said colder liquid during its course in said truncated tubes to obtain a dragging effect by action of the colder liquid from said truncated tubes upon "the warmer Water coming down along the interspace existing between the truncated tubes and the downcomers, thus activating the circulation, and finally to obtain the mixing of the colder water from the truncated tubes with the warmer water of the downcomers.

The invention will be described with reference to the attached drawings, which are intended to have only an exemplifying and not, in any way, a restrictive purpose.

FIG. 1 and FIG. 2 illustrate a section of two diiferent realizations of the heat exchanger;

FIG. 3 shows a heating boiler having a number of heat exchangers according to the invention;

FIG. 4 shows a heating boiler having a different construction, still according to the invention;

FIG. 5 is a perspective view, with partial cutaways, of a heating boiler having two sets of heat exchangers according to the invention.

With reference to FIG. 1, A indicates the upper collector, having a tubular shape; to A are connected a downcomer 1 and a boiler tube 2, both of which are also connected to a lower collector B. It is of course understood that there will be a number of tubes 1 as well as a number of tubes 2, arranged in two rows perpendicularly to the plane of the drawing, said tubes being either in contact with each other or at a convenient distance from each other. Inside of the upper collector A there is axially placed the water intake duct C, its outer diameter being substantially smaller than the inner diameter of the collector A. The water duct C brings in the colder feed liquid coming back from the utilizing apparatus. To the tube C are connected truncated tubes or iniector nozzles D, each of them being co-axially placed inside a downcomer 1 and being shorter than the latter. The colder liquid from the tube C comes in said tubes D according to the arrow X and receives a pre-heating by action of the warmer liquid which comes down, according to the arrows Z, along the interspace existing between the tube 3,046,955 Patented July 31, 1%62 I exposed to the furnace, thus preventing the formation of corrosive deposit. Besides, the water circulation in the wanted direction will be activated by way of the injection action of the liquid from the tube D upon the surrounding liquid. In this area the two liquid streams mix together thus giving Way to a single stream, which in its course along the tube 2, according to arrow K, will be heated, and on reaching the upper collector A will divide into two parts, the first one being taken away to the utilizing apparatus, while the second one will resume its circulation through the interspace existing between the tubes 1 and D.

The tube C might be divided into two portions by means of a horizontal, longitudinal diaphragm 3 (shown with a dotted line), in order to use the lower portion to bring in the colder liquid, and the upper portion to take away or discharge the hot water towards the utilizing apparatus, provided that said upper portion of the tube C be suitably perforated, so as to allow the hot water from the collector A to enter C. i

In FIG. 2 a similar arrangement is shown, in which the various parts are designated by the same letters or numerals as in MG. 1, but'with an index. The upper collector comprises two tubular element s Qr drums A connected together by means of the tubes 4. The boiler tubes 2 are connected to'the lower tube A of the collector, having in its center the tube 5 which takes away the hot water. The downcorners l are connected to the upper collecting tube A.

in FIG, 3 the furnace E comprises two rows of tubes contacting each other along a generatrix, which are corinectcd to the upper collector A and to the lower collector B". The downcomers 1" and the boiler tubes 2 alternate with each other, their function being deter mined by the presence of the tubes D", which exist only inside of the downcomers. The tubes D" are connected to the tube C" which brings in the colder liquid and is placed inside of the upper collector A". Through the nosepiece 5 of collector A" the hot water is delivered to the utilizin apparatus. Through the collector B" the liquid from the downcomers goes into the boiler tubes 2", as shown by the arrows. This passage may take place partly among tubes placed at the same side with respect to the furnace, and partly among tubes placed on opposite sides. It is of course understood that'two distinct lower collectors, placed for instance laterally may also exist, in which case the lower parts of the furnace will not be delimited by the tubes. In such a case the circulation within the lower collectors will be obviously limited to the downcomers and the boiler tubes which belong to the same side.

In the example of FIG. 4 inside of the collector A", are placed two conduits, namely: 0", which brings in the coider liquid and to which are connected the tubes D, and F, the latter having the holes 7, for taking away the hot water. The furnace B, because of the U-shaped form of the boiler tubes 2", is still surrounded by the tubes.

In FIG. 5 there is shown a heating boiler comprising two units which are similar to the one of FIG. 4, except that the downcomers 1" and the boiler tubes 2"" are so interspaced as to allow a reciprocal interspersing; the two units are specularly symmetrical with each other. The heating boiler of FIG. 5 also difiers from the one of FIG. 4 in that the single tube C" of each unit is divided into two portions by means of a diaphragm 3"", as illustrated in FIG. 1, and because of the presence of a number of aux liary heating tubes 8 connecting the upper collector A"" to the lower collector 8" so as realize a second gas 3 pass between said tubes 8 and the tubes that surround the furnace.

The examples given in the-present description are only intended to have an exemplifying purpose, and are not to be considered as being in any way restrictive of the invention. The present invention can also be realized with minor modifications without departing from its fundamental conception.

Iclaim:

1. In a boiler, a heat exchanger comprising an elongated upper collector and an elongated lower collector, downcomer and boiler tubes interconnecting said collectors, conduit means disposed in and enclosed by said upper collector comprising a feed water intake conduit and a fluid discharge conduit, an injector nozzle disposed centrally at the interior of each downcomer tube and extending therein throughout at least one-third of the length thereof, said injector nozzles being connected to said intake conduit for injecting feed water into said downcomer tubes, the exterior of each injector nozzle defining with the internal surface of its downcomer tube an annular space for the circulation therein of some of the fluid heated in said boiler tubes, said discharge conduit comprisinga horizontal conduit member including an upper wall having perforations to admit for subsequent discharge some of the fiuid heated in said boilertubes 2. In a boiler, as claimed in claim 1, said conduit meanscomprising a horizontal pipe having a longitudinal partition dividing the pipe interior into upper and lower portions, said lower portion forming said feed water intake conduit, said upper portion forming said discharge conduit.

3. In a boiler, as claimed in claim 1, said upper co1 lector comprising two intercommunicating vertically superposed collector drums, said intake conduit including a pipe disposed in the upper drum, said discharge con duit including a pipe disposed in the lower drum, said downcomer tubes being connected to the upper drum, and said boiler tubes being connected to the lower drum.

, 4; In a boiler, as claimed in claim 1, said downcomer and, boiler tubes being arranged in alternating sequence 7 V screens longitudinally of said collectors and abutting against each other forming uninterrupted walls of said boiler.

5. in a boiler, as claimed in claim 1, said downcomer tubes abutting against each other-to form a first boiler wall, said boiler tubes being U-shaped and abutting against each other forming a second boiler ,wall.

6. In a boiler, at least two heat exchangers, each heat I exchanger comprising an elongated upper'collector and an elongated lower collector, downcomer and boiler tubes interconnecting said collectors, conduit means disposed in and enclosed by said upper collector comprising 'a feed water intake conduit and afluid discharge conduit, an injector nozzle disposed centrally at the interior of each downcomertube throughout at leasttwo-thirds of the len th thereof, said injector nozzles being connected to said intake conduit for injecting feed water into said downcorner tubes, the exterior of eachinjector nozzle defining with the internal surface of its downcomer tube an annular space for the circulation therein of some of the fluid heated in said boiler tubes, said discharge'conduit comprising a horizontal conduit member including an' upper wall having perforations to admit for subsequent V discharge some of the fluid heated in said boiler tubes, the tubes of each heat exchanger being interspersed and in abutment forming uninterrupted Walls of said boiler, and

aum'liary boiler tubes between the upper and lower collector of each heat exchanger outside of said Walls.

7. In a boiler, as claimed in claim 6,--the tubes and conduits of said two heat exchangers being arranged specularly symmetrically relative to each other.

References Cited in the tile of this patent UNITED STATES PATENTS Italy May 12, 1951 

